1. Field of Invention
This invention relates to automotive equipment and is particularly directed to combined oil filters and coolers.
2. Prior Art
Modern automotive engines tend to be made of light weight materials, such as aluminum, and to be designed to operate at high rates of revolution. Unfortunately, this combination causes the engine temperature to be quite high which tends to cause the lubricating oil to lose its viscosity and, hence, its ability to protect the engine against damage by friction and water. Ideally, the temperature of the motor oil should be kept below about 190.degree. Fahrenheit. However, this value is often exceeded in modern automotive engines.
Because motor oil eventually becomes contaminated with sludge, metal particles and other debris, it is common practice to connect an oil filter in the oil line and to cause the oil to be circulated through the filter to remove the contaminants. Also, because of the heat problems, mentioned above, it is conventional to mount the oil filter in a position external to the engine to provide some degree of cooling as the oil passes through the filter. Unfortunately, with modern automotive engines, the flow rate of the oil through the engine is such that the dwell time of the oil in the filter is insufficient to adequately cool the oil. It has been proposed to overcome this problem by providing separate radiators for the oil. However, such radiators are quite expensive to install and maintain and require considerable redesigning of the oil flow system. Consequently, such radiators are found only as original equipment on very expensive automobiles and are not found on moderately priced cars or as retro-fit equipment. Thus none of the prior art oil filters and coolers have been entirely satisfactory.
A search in the U.S. Patent Office has revealed the following references:
______________________________________ U.S. Pat. No. INVENTOR ISSUED ______________________________________ 3,042,215 F. R. Gruner July 3, 1962 4,369,113 J. Stifelman Jan. 18, 1983 4,454,037 R. H. Conterio et al June 12, 1984 ______________________________________
The patents to Gruner and Stifelman teach conventional oil filters, while the patent to Conterio relates to an insulating jacket for oil filters which may have utility in arctic conditions, but is the antithesis of the present invention.